Symptoms
Submitting a request from service portal throws errors like 'Evaluator: java.lang.NullPointerException' with possibly failing widgets like Ticket conversation and errors/messages in log similar to 'com.glide.glideobject.GlideDateTime.addSeconds(GlideDateTime.java:1172)' and 'SEVERE *** ERROR ***performing addSeconds with invalid GlideDateTime'
Release
Any release supporting Service Portal
Cause
In most cases there was a customized business rule referencing DateTime type fields and causing issue
Resolution
The issue was due to a customized business rule which got resolved after customer deactivated the business rule or fixed the script where the datetime field was referenced. A hint to find which business rule is causing the problem maybe to check the Updated field for any recent updates.